Bud of Magnolia: an Herbal Anti-histamine?

Introduction to Bud of Magnolia:

In Chinese medicine, there is an herb called Xin Yi (辛夷), directly translated as pungent barbarian. It is the dried bud of the magnolia flower.
Xinyi has traditionally been used as part of cold and flu formulas, and is particularly known to clear the nose. 《名医别录》says that it can “通鼻窍.”

Known functions:

  • constrict the blood vessels in the nasal mucus membrane
  • speed up absorption membrane secretions
  • reduce inflammation
  • Other functions include:
  • local anesthetic
  • stimulate the womb’s contraction
  • increase peristalsis
  • lower blood pressure
  • sedative
  • pain-relief
  • anti-allergy

Which is why I see it as a natural antihistamine.

On anti-histamines:

Of relevance here are two types of cells that exist in our body. Mast cells (肥大细胞) hang out in the loose connective tissue, while Basophils (嗜碱性细胞) are a type of white blood cell. Both contain granules, inside of which are different substances that cause allergic reactions. Histamine is one of these substances that hang out in these granules.

Histamine is more prevalent on the skin, the bronchial mucus membranes and the intestinal mucus membranes. It also exists in the central nervous system, helping it do its job. For many people who have common allergic reactions, the allergen causes the mast cells to release these granules, and these histamines bind to histamine-receptors of nearby cells. This causes an allergic reaction.

There are three types of histamine receptors, but the one we are concerned about are the H1 receptors. When histamines bind to H1 receptors, the following happens:

  • the smooth muscles of the bronchial tubes, gastrointestinal walls, womb contract.
  • Capillaries (especially those on the skin) dilate, become more porous and exudate, causing water retention.
  • the atrium of the heart contracts more strongly, while the transmission pathway of the heart is slowed down.

A H1 antihistamine aka H1 receptor antagonist is able to bind to the H1 receptors, preventing our bodies histamines from binding to them, hence preventing an allergic reaction. Put specifically, it is able to:

  • dilate the smooth muscles of the bronchial tubes hence preventing a bronchial asthma attack (ketotifen is good for this); reduce constriction of gastrointestinal walls, treating certain types of vomiting; relax womb contraction.
  • prevent and treat all sorts of skin problems e.g. pruritis, edema, contact dermatitis, allergic dermatitis.
  • help to calm down and induce sleep by suppressing the central nervous system.

Is Bud of Magnolia just another anti-histamine?

So, the question is: will using Magnolia bud result in the following side effects associated with using an H1 receptor antagonist?

  • Cause sedation, somnolence, fatigue, as a result of suppressing the CNS.
  • Dryness in the eyes, mouth, intestines.
  • Mild reactions in the digestive system, e.g. loss of appetite, nausea, constipation or loose stools.

From a TCM point of view, it’s probably the pungent (辛) quality of this herb that causes dryness, because pungent herbs are aromatic in nature and “香芳化湿”(aromatics eliminate damp). Stronger aromatic herbs not only take away dampness, they are strongly drying and are not good for yin-deficient people –  who often present with dryness, at times associated with heat. Dryness taken broadly may not just manifest as dry eyes, intestines and mouth.

Sources: 《中药学》,中国中医药出版社;《药理学》,上海科学技术出版社